Drug abuse with its potential for drug overdose poisonings, both intentional and accidental, is a major rising health problem in the United States. Factors contributing for this increase are the rapid increase in the number of prescriptions written for drugs possessing abuse potential (eg. analgesics and psychopharmacologic agents) and the rapid rise in the national geriatric population (eg. consume large numbers of prscription drugs). Health care professionals have long recognized the need for rapid analytical methods for determining which class of drug or drugs are present in an emergency situation. Numerous methods are available for determining drug levels in biological fluids but all require diagnosis in a laboratory environment. Most of the available assays require trained personnel, expensive equipment, and are slow in determining the drug present. Radioimmunoassay procedures produce the additional problem of radioactive waste disposal which is presently, and will increasingly become a major problem in the future. Our NIDA SBIR Phase I results provided a basic proof-of-concept for the development of a strip enzyme immunoassay which will be useful for emergency situation determination of which class of drug or drugs was then in overdose. The assay is simple, fast (less than six minutes), noninstrumental, and thus easily portable for use by emergency personnel at the scene of the suspected overdose. Further development of this assay will allow the determination of which drug class is present and thus allow for general supportive measures prior to arrival at medical facilities.